Portable self-propelled scaffold



IApril 23, 1946, l- H. F. MccLAlN PORTABLE vSELF-PROPELLED scAFFoLDFiled March 23, 1945 7 Sheets-Sheet l INVENTOR.

IZZZZIc Claim .April 23, 1946. H. F. MccLAxN PORTABLE SELF-PROPELLEDSCAFFOLD Filed March 23, 1945 April 23, 1946; v H. F. MCCLAIN PORTABLESELF-PROPELLED scAFFoLD r Filed Marel; 23, 1945 7`sneets-.sheet 4 v elk.I .l. lf!

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PORTABLE SELF-PROPELLED SCAFFOLD Filed March 25, 1945 .7 sheets-sheet 5www April 23, 1949.

` H. F. MCCLAIN PORTABLE SELF-PROPELLED scAFFoLD INVENTR. l

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H. F. MCCLAlN iled March 25, 1945 A PORTABLE SELF-PB OPELLED SCAFFOLDpril 23, 1946.

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Patented Apr. 23, 1946 UNITED STATES PATENTl OFFCE- PORTABLESELF-PROPELLED scAFFoLn Hugh F. McClain, Long Beach, Calif. ApplicationMarch 2s, 1945, serialNo. 584,318 L l 10 Claims.

This invention relates to a portable self-prop elled scalold, theprimary object of the invention being to provide a scaffold especiallydesigned for use in dry docks or ship-building yards.

An important object of the invention is to provide a scaiold of thischaracter including a pivoted staging section mounted on a movablesupport, so that the staging may be tilted and secured in its adjustedtilted positions to move the catwalks carried thereby, in proximity tothe ship underrepair.

Another important object'of the invention is to provide a scaffoldincluding a pivoted section on which the catwalks are adjustableindependently of each other and in horizontal planes so that the forwardedges of the catwalks may be moved to positions adjacent to the hull ofthe ship, to the end that the workers standing on the catwalks may haveeasy access to their work.

With the foregoing and other objects in View which will appear as thedescription proceeds, the invention consists of certain novel details ofconstruction and combinations ofrparts hereinafter more fully describedand pointed out in the claims, it being understood that changes may bemade in the construction and arrangement of parts without departing fromthe spirit of the.

invention as claimed.

Referring to the drawings t Figure 1 is a side elevational view of ascaffold constructed in accordance with the invention, the pivotedstaging sectionthereof being shown in its adjusted position in dottedlines.

Figure 2 is a rear elevational view of the scat fold. Y

Figure 3 is a sectional view taken on line 3--3 of Fig. 2.

Figure 4 is a sectional view taken on line 4 4 of Fig. 3. K

Figure 5 is a sectional view `taken on line 5--5 of Fig. 1. v Y

Figure 6 is a sectional View taken on line 6 6 of Fig. 2.

Figure 7 is a sectional view taken on line 'I-'I ofFig. 6. i

Figure 8 is a sectional View taken on line 8-,8

of Fig. 6. Y Figure 9 is a sectional view taken on line 9-9 of Fig. 3.

Figure 10 is a sectional view taken on line Ill--Ill of Fig. 1.

Figure 11 is a sectional view taken on line II-II of Fig. 2.

(Cl. 304-2) I Figure 12 `is a sectional view taken on line I2-I2ofFig.6.f Figure 13 is an enlarged elevational view illustrating one of thebrakes.

5 Figure 14 is a sectional View taken vonl line Ill-IdofFig. 1. ,I Y.

Referring to the drawings in detail, the scaffold embodies a rectangularframe comprising! front and rear channel bars 5 and end bars 6,the barsl0 5 and 6 being welded together at their ends providing anexceptionally rigid structure. y,

This frame provides the chassis for'the 'supporting truck, and hasmounted at itsiorward side, caster rollers I.

l5 At the rear corners of the frame, are tubular bearing members 1,disposed vertically, andsecured to thebar5 at therear of the-frame, andthe rear ends of the end bars 6, by means or the angle plates 8, whichare welded to the rear ybar 5 and end bars 6. The lower ends of thetubular bearing members 'Iv are enlarged and formedwith annular groovesto receive Athe ball Abearings 9.

The reference character I0 indicates the forks for thev traction wheelsofthe truckl orA carriage,

the forks I0 having openings toA receive the axles II on which thetubular bearings I2 aremounted.' The tubular bearings are secured withinthe hubs of the wheels I3 to move therewith. Bev-y eled pinions I4 aresecured to the bearings I2,

and are in mesh with the pinionsv I5 secured to the lower ends of thelshaft IE. The shaft I 'is mounted in the bearings II and I8, thebearings fI'I being secured to the forkslll, while' the bear-V ings I8extend inwardly yfrom the tubular shafts I9 that extend upwardly fromthe forks it. in the construction of the forks I0, disk-like bearings 2U.are provided, which bearings are valso formed 'with grooves to Areceivethe "ball ',bear- 40 ings 9.

closed by the disks 24 which disks provide ,sup-4 ports for the bearingarms 25 which depend therefrom. Y

The shafts 26 extend through' the 'disks 2d and have their lower endsdisposed'v within bearing openings formed in the bearing arms 25.

The bearing arms 25 are spaced from the. disks 24, providing clearancesvfor the gears ELthat in turn mesh with thegears 28 secured to` the shaftI6. Mounted on the upperv .endsof the shafts 26 are substantially largepinions 2Q- that mesh with the pinions 3B secured to the ends of thepower shafts 3l which are mounted in the bearings 32 that are secured tothe tubular bearing members 1. Differential gearing of the usual andwell known construction, is provided in the gear housing 33 and includesa gear mounted on one end of the shaft 34 which carries the beveled gear35 at one end thereof.

Secured to each shaft 3| aat a. point adjacent to the diierentialgearing housing 33., is a brake drum 35 `and a brake band 35, the brakebands being operated to grip the brake drums to hold either of theshafts 3l against movement in guiding the scaiold. i

Brake-operating levers 31 connect with the brake bands and provide meansfor operating the brake bands. These brake-operating levers 31 areconnected with the pedals 38 for operation by the operator of thescaffold.

A platform 39 forms a part of the truck and extends between the end barsof the frame of the truck. The platform provides a support for the powerplant which inthe present showing is in the form of a motor 4B whichtransmits movement to the shaft 4I through the belt 42 operating overthe pulley 43 mounted on the end of the motor shaft, and thesubstantially large pulley 44 .secured to the shaft 4|. Spaced pinions45 and 46 are loosely mounted onrthe shaft 4i, the pinion 46 being heldspacedfrom the pinion 41, by means of the Abearing48. The pinion .41 isin mesh with the gear 35V to direct motion to the shaft 34 in operatingtheshaft V3i, through the differential gearing.

Also mounted on the shaft 4| and being in mesh with the gear 35, is apinion 48'. Pinion 48 is also loosely mounted on the shaft 4l, thepinion 49 being in.r mesh withthe gear 5B which in Yturn is in mesh withthe pinion lV which is loosely mounted on the shaft'4i. Gear 5,0 ismounted on one end of .the shaft 52 which carries the worm gear 53 atits free end, the worm gear 53 being in mesh. with the gear t4 securedto the shaft-23.

Disposed between the pinions 45 and 46, are clutch members 5'5 and 58,which are operated by means of the clutch lever 51, to connect either ofthe pinions 45 or 46. to the shaft 4l.

.Clutch members 58 and 59 are also connected with the shaft 4l' and,vare adapted to be moved into engagement with the pinions. 41 or 48", toconnect them to the shaft 4l. These clutch members 58 and 59 areoperated by means of the clutch lever BU. Clutch members Yill and E2operated by means of the clutch lever 63, operate between the .pinions49 and5l and are adapted to connect either pinion to the shaft 4I tooperate the gear 58 and shaft 52 .eitherin a clockwise direction or ananticlockwise direction, to guide the truck.

Rising from the truck, and being rigidly connected therewith, is a.supporting frame for the movable tower section of the scaffold, whichcomprises rear bars 64 and 65, and front bars 66, the bars 64 and 65being connected with the front bars 66 by means of the horizontal bars61, the main or rear bars of the vertical frame ling connected by meansofY the transverse bar Bearings B9 are secured to the. rear bars 64 andprovide supports. for the shaft that also extends through the bearings1|.r secured to the rectangular frame 12 that is secured to the rearbars. The ends of the shaft 10are mounted in bearings 13 that aresecured at the ends ofthe frame 12. The shaft 14 carries the pinion 15at its lower end, the pinion 15 being in mesh with the pinions 5 and i6so that rotary movement may be directed from the shaft 4I to the shaft14 in a direction either to the right or lett, for purposes to behereinafter more fully described.

As clearly shown by Fig. 2 of the drawings, the shaft 14 extends to apoint adjacent to the gear 'E6 mounted on the shaft 10, the shaft 1dcarrying the worm 1i which is in mesh with the gear 16 to rotate thegear and shaft 18. Beveled gears 'I8 are mounted on the shaft 10, andthese beveled gears mesh with the pinions 19 that are secured to therear ends of the screws 88 that move through the threaded members 8i,which are provided with Shanks 82 that extend through openings in thevertical rear bars of the adjustable tower, forming a part of thescaold. The connection between the members 8i and rear bars of the toweris such that the members 8l may pivot with respect to the tower. Thethreaded members 88, as shown by Fig. ll, also move through tubularbearings 83 which are pivotally mounted on the shaft 10 of thestationary upright frame. By operating the clutch lever 51, it ispossible to rotate the threaded members or screws 86 to move the towerto its adjusted position, or return the tower to a position adjacent tothe stationary supporting frame of which the bars 64 and 65 form a part.

The adjustable tower embodies front and rear bars 84 and respectively,which are vconnected by the channel bars 3B by means of bolts-86', thechannel bars 85 Vbeing of lengths to extend appreciable distances beyondthe front bars 84, as clearly shown by Fig. l of the drawings. Thesechannel bars 8S are arranged in predetermined spaced. relation withrespect-to each other and are pivotally connected with the bars 84 bymeans of bolts 84 Vwhile the rear ends of the bars'o are connected withthe bars 85 by the bolts 81, so that .the tower may-swing from theVertical position shown in full lines in Fig. 1 of the drawings, to theinclined position asshown in dotted lines in Fig. 1 ofthe drawings.

The swinging tower is pivotally connected to the stationary supportingframe, by means of the bolts 84' and 81, the latter bolts being shown asextended through the bars 64 and V(i5 ofthe supporting frame and bars 85of the tower.V Angular base bars 88V connect the rear bars 85 to bracethem against movement with respect to each other. The free edges of thechannel bars86 are turned inwardly, providing tracks 89, as shown byFig. 8. Secured to the channel members 86 and disposed within the connesof the flanges thereof, are pulleys '90 over which the cables 9|operate. Y

The c'atwallrsv indicated by the reference character 92 embody ooringboards 93 that' are bolted to the angle bars 94 by means 'of the bolts95, which are shown as passing through openings in the ooring, andthrough aligning openings in the angle bars 94. The openings in theflooring at one end of -ea-ch catwalk, are elongated as shown at 96, tothe end that the ooring may be adjusted from the full line position asshown by Fig. l0 of the drawings, to the dotted lineposition, whereinthe outer edges of the catwalks may ,be moved to positions to conform tothe .general contour of the hull of a ship with whichthe scaffold isbeing used. I

The angle bars 94 provide supports for the grooved supporting wheels 91which are mounted on the shafts 98 that extend through the angle bars 94and are secured.y thereto. by means 'of the nuts 99. The grooved'supporting wheels 91. operate over the tracks 89, 'as shown -by Fig?."7. of thedrawings. f ff Supported by the angle bars 94 and movabletherewith, are pairs of brake arms that are pivotally mounted on thebolts |0| that are shown as extended through the housing |02. Springs|03 Vconnect the brake arms of"opposite'pairs, as shown by Fig. 6 of thedrawings. These brake arms |00, are relatively long so that when theyare moved in one direction, they will set upa binding action with thetracks 89. :The ends of the arms |00 are forked, so that they fit overthe tracks. g

Mounted for sliding movement on the housing |02, is a plate |04 that hasinwardly turned parallel anges |05 which'are so positioned that when theplate |04 is moved longitudinally of the housing, the ends of the angeswill engage the brake arms |00 to force the arms forwardly out vofcontact with the tracks. The arms at the opposite end of the housingwill trail,` allowing theV catwalks lto be adjusted with respect to thetower, so that predetermined catwalks may be moved outwardly to contactwith the hull of the ship with which the scaffold is being used, so thatthe operators may work in close proximity to the hull of the ship. Thecables 9| which connect with the plate |04, move over the pulleys 90,and extend to positions wherein the operators may have easy accessthereto to accomplish the adjustment of the catwalk as described. Itwill be seen that under normal conditions, the springs |03 will operateto cause the free ends of the brake arms to frictionally engage thetracks 89, securing the catwalks in their positions of adjustment. Whenit is desired to move the catwalks in the opposite direction, the cable9| at the,l opposite end of the plate |04 will be operated to move thebrake arms at this end of the plate, out of contact with the tracks,whereupon the catwalks may be moved in the opposite direction, the brakearms at the opposite end of the plate, trailing during this movement.

In the operation of the device, the motor 40 is set in motion 'directingrotary movement -to the shaft 4|. The clutch lever 00 is now operated toclutch either the pinions 41 or 48 to the shaft, whereupon rotarymovement is directed to the gear 35. The shaft 34 is now operated todirect rotary movement to the shaft 3| through the differential gearingwithin the gear housing 33. The shaft 3| operates the shaft I6, throughthe gearing shown by Fig. 9 of the drawings, and these shafts rotate thewheels I3, through the beveled pinions |4 and pinions I5.

When it is desired to turn the truck in moving the truck to its properposition with respect to the ships hull, the clutch lever 63 is operatedto rotate the shaft 23 which in turn rotates the forks |0 in which thewheels I3 are mounted. The desired brake pedal is now operated to lockone of the shafts 3| while the other shaft rotates the wheel at theopposite end of the truck, after the truck has been moved to a positionadjacent to the hull of the ship, the clutch lever 51 being operated torotate the shaft 14 and screw 80 to move the tower to the desiredposition. In order to adjust the catwalks so that they will move topositions to conform with the contour of the hull of the ship, thecables 9| are operated in a manner as previously described to move thecatwalks independently of each other. The catwalks will 'sand from sandblasters or the like.

Inview of the foregoing detailed description, it is believed that afurther .detailed description as to the operation of the device isunnecessary.

What is claimed is:

l. A scaffold embodying a truck, a vertical supporting frame mounted onthe truck, a tower pivotally mounted at the upper end of the supportingframe, a plurality of vertically spaced catwalks mounted on the towerand extending forwardly therefrom, and an adjusting means for moving thecatwalks in horizontal planes at right angles to the tower,independently of each other.

2. A scaiold embodying a truck, a vertical supporting frame mounted onthe truck, a tower, means for mountingA the tower for swinging movementon the supporting frame, adjusting screws adapted to swing the tower onthe supporting frame,.said adjusting screws adapted to also hold thetower in its positions of adjustment, superposed catwalks mounted on thetower and adapted to extend beyond the front edge of the tower, andmeans for adjusting the catwalks at right angles to the tower and inhorizontal planes towards or away from the tower independently of eachother.

3. A scaffold embodying a truck, a support rising from ther truck, atower mounted for vertical swinging movement on the support, adjustingscrews adapted to move the tower to various angular positions withrespect to the support, catwalks mounted on the tower and arranged invertical spaced relation with respect to each other, and means foradjusting the catwalks in a line at right angles to the tower and withrespect to each other in horizontal planes.

4. A scaiold embodying a truck, a support mounted on the truck, a towerpivotally mounted on the support and being extended an appreciabledistance above the support, catwalks mounted on the tower in verticalspaced relation with respect to each other, and means for moving thecatwalks in horizontal planes independently of each other in a. line atright angles to the tower.

5. A scaifold embodying a base, a support mounted on the base, a towerpivotally connected to the support at a point intermediate the ends ofthe tower, lchannel bars providing tracks, secured to the tower,catwalks, said catwalks including rollers movable over the tracks,whereby said catwalks may be extended beyond the front of the towerindependently of each other, pairs of brake arms mounted on eachcatwalk, said .Y brake arms adapted to normally prevent movement of thecatwalks by frictional contact with said tracks, operating cables, meansoperated by the cables for moving predetermined brake arms out ofcontact with the track, whereby said catwalks are extended beyond thefront of the tower, I

independently of each other.

6. A scaffold embodying a base, a tower mounted on the base for verticalswinging movement, movable catwalks supported on the tower and beingdisposed beyond the front of the tower, and means for advancing thecatwalks in horizontal planes at right angles to the tower, towards andaway from the tower independently of each other beyond the normalretracted positions of the catwalks. Y

7. AV scaffold comprismg a base, a tower 'niv otally mounted on thebaseand embodying vertical bars, channel bars ypivotally connected Withsaid vertical barst .said channel bars having their open sides disposedinwardly, providing tracks, said channel hars being extended forwardlybeyond the tower, catwalks mounted on the extended ends Vof the channelbars of the tower and being disposed in vertical kspaced relation withrespect to each other, rollers mounted on the catwalks and operatingover the tracks whereby said catwalks may be extended beyond the forwardends of the channel members, independently of each other.

8. A scailold comprising a support, a tower pivotally ,mounted on thesupport, threaded pivoted bearings mounted on the tower, threadedmembers mounted on the support and being movable through the threadedbearings whereby said tower may `be swung to various angular posit-ionswith respect to the support, and a plurality of fcatwalks arranged invertical spaced relation with each other on the tower.

9. A device of the character described, comprising a tower embodyingvertical bars, channel bars pivotally connected to the vertical bars,said channel bars yhavingr their open sides :disposed inwardly providingtracks, movable catwalks including angle bars, rollers mounted on theangle bars, said rollers operating over the tracks, pairs of pivotallyconnected inclined brake arms mounted on each catwalk, said .brake armsr'l'laving :forked ends adapted to straddle said tracks, frictionallyengaging the tracks and normally securing the catwalks against movement,means for movin-g the catwalks along the'tracks, said moving means.adapted to -disengaee certain of said arms and tracks. i l0. A deviceof the character described, comprising a tower, horizontal tracksmounted on lthe tower, catwalks movable over the tracks, pairs ofpivoted braker arms Amounted on the catwalks, means for urging saidbrake arms into frictional contact with the tracks, normally securingsaid catwalks against movement, means for moving the catwalks'along thetracks, and said catwalkmoving means adapted to release said brake arms.l

HUGH F. MCCLAIN.

